Some 2015 Lincoln Navigator vehicles built on or before July 17, 2015, might exhibit a warning light on, with diagnostic trouble code (DTC) P0087 and possible loss of power.
Using the Ford IDS service tool or equivalent scan tool, check for DTC P0087. If this DTC is the only one present, replace the fuel injection pump. The new pump is available as P/N BL3Z-9350-C. Also required are two bolts P/N W503297-S900 and one nut P/N W520100-S437.